Secondary polyphenol metabolites form a wide group of diverse chemical compounds which exist both in land plants and in aquatic macrophytes (Waterman and Mole, 1994, Analysis of phenolic plant metabolites, Blackwell Scientific Publications: Oxford, Great Britain). From among these compounds, phloroglucinol as well as its derivatives are widely used in industry, and notably in the pharmaceutical, cosmetic or further agri-feed industries. More recently, phloroglucinol and its derivatives have shown potentially interesting activities for humans in pharmacology (production of reaction intermediates for hemi-synthesis of chemical compounds), in medicine (antimicrobial, anti-HIV, anti-cancer, anti-diabetic, anti-allergic, anti-inflammatory properties) or cosmetics (anti-age effect) which makes them natural molecules with a very interesting potential (Singh I P et al., 2009, Expert Opin Ther Pat, 19: 847-66, for a review). At the present time, only phloroglucinol synthesized chemically is marketed as a musculotropic antispasmodic drug (under the name of Spasfon® in France). Moreover, mixtures of products are also marketed like extracts of Ascophyllum nodosum by the Algues & Mer Ouessant corporation (29, France), products like Seanol™, extracts of Ecklonia cava or further HealSea, extracts of Fucus vesiculosus by the Diana Naturals corporation (35, France) and a few other companies worldwide.